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Yuval Yeret

James Shore: The Art of Agile Development: Simple Design - 0 views

www.jamesshore.com/...simple_design.html

james shore art development

shared by Yuval Yeret on 13 Jan 15 - No Cached
  • Simple Design AudienceProgrammers Our design is easy to modify and maintain
  • Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away. —Antoine de Saint-Exupéry Any intelligent fool can make things bigger, more complex and more violent. It takes a touch of genius and a lot of courage to move in the opposite direction. —Albert Einstein
  • When writing code, agile developers often stop to ask themselves, "What is the simplest thing that could possibly work?" They seem to be obssessed with simplicity. Rather than anticipating changes and providing extensibility hooks and plug-in points, they create a simple design that anticipates as little as possible, as cleanly as possible. Unintuitively, this results in designs that are ready for any change, anticipated or not.
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  • I don't think XP and patterns are conflicting. It's how you use patterns. The XP guys have patterns in their toolbox, it's just that they refactor to the patterns once they need the flexibility
  • You Aren't Gonna Need It (YAGNI) This pithy XP saying sums up an important aspect of simple design: avoid speculative coding. Whenever you're tempted to add something to your design, ask yourself if it supports the stories and features you're currently delivering. If not, well... you aren't gonna need it. Your design could change. Your customers' minds could change.
  • We do this because excess code makes change difficult. Speculative design, added to make specific changes easy, often turns out to be wrong in some way, which actually makes changes more difficult. It's usually easier to add to a design than to fix a design that's wrong. The incorrect design has code that depends on it, sometimes locking bad decisions in place.
  • Once and Only Once
  • avoid duplication. "Once and only once" is the Extreme Programming phrase. The authors of The Pragmatic Programmer [Hunt & Thomas] use "don't repeat yourself," or the DRY principle.
  • Self-Documenting Code Simplicity is in the eye of the beholder. It doesn't matter much if you think the design is simple; if the rest of your team or future maintainers of your software find it too complicated, then it is.
  • What if we know we're going to need a feature? Shouldn't we put in a design hook for it? In XP, the plan can change every week. Unless you're implementing the feature that very week, don't put the hook in. The plan could change, leaving you stuck with unneeded code.
  • Results When you create simple designs, you avoid adding support for any features other than the ones you're working on in the current iteration. You finish work more quickly as a result. When you use simple design well, your design supports arbitrary changes easily. Although new features might require a lot of new code, changes to existing code are localized and straightforward.
  • Simple design requires continuous improvement through refactoring and incremental design and architecture. Without it, your design will fail to evolve with your requirements. Don't use simple design as an excuse for poor design. Simplicity requires careful thought. As the Einstein quote at the beginning of this section says, it's a lot easier to create complex designs than simple ones. Don't pretend "simple" means "fastest" or "easiest.
  • Until recently, the accepted best practice in design followed the advice Erich Gamma now disavows: "The key to maximizing reuse lies in anticipating new requirements and changes to existing requirements, and in designing your systems so they can evolve accordingly."
Yuval Yeret

Larman's Laws of Organizational Behavior - Craig Larman - 0 views

www.craiglarman.com/...index.php

agile-change-management-list

shared by Yuval Yeret on 08 Jul 14 - No Cached
  • Yuval Yeret on 08 Jul 14
     
    "Larman's Laws of Organizational Behavior After decades of observation and organizational consulting, here are Larman's Laws of Organizational Behavior. These are observations rather than laws to follow ;) 1. Organizations are implicitly optimized to avoid changing the status quo middle- and first-level manager and "specialist" positions & power structures. 2. As a corollary to (1), any change initiative will be reduced to redefining or overloading the new terminology to mean basically the same as status quo. 3. As a corollary to (1), any change initiative will be derided as "purist", "theoretical", and "needing pragmatic customization for local concerns" -- which deflects from addressing weaknesses and manager/specialist status quo. 4. Culture follows structure. i.e., if you want to really change culture, you have to start with changing structure, because culture does not really change otherwise. and that's why deep systems of thought such as organizational learning are not very sticky or impactful by themselves, and why systems such as scrum (that have a strong focus on structural change at the start) tend to more quickly impact culture. i discovered that john seddon also observed this: "Attempting to change an organization's culture is a folly, it always fails. Peoples' behavior (the culture) is a product of the system; when you change the system peoples' behavior changes." "
Yuval Yeret

CIO Perspectives: A Conversation on Agile Transformation, Part 2 - 0 views

www.borland.com/...cio-perspectives-part-two.html

agile transformation

shared by Yuval Yeret on 15 May 09 - Cached
  • Part 2
  • The thinking is that IT is mission-critical, so let's not change things without giving it a lot of thought and a lot of consideration
  • The really hard part is around the people transformation - getting developers to work side-by-side with testers and users is a completely foreign concept.
  • ...8 more annotations...
  • The reason there's been so much turnover of CIOs in the last ten years is because the end users – the CEOs, the CFOs and the division heads – are unhappy with the results. When IT professionals realize this, and realize that something like Agile gives them the opportunity to create better value for their businesses, then they're going to be a lot more willing to adopt it. I hope that development organizations are starting to see around that corner.
  • We WANT to go Agile. How do we overcome the skepticism at the CXO level?"
  • My recommendation would be "try it." Agile doesn't equal risk, but changing development methods does equal some risk
  • t can be a big deal to say: "I'm going to change our development methodology." It makes people sit up and want to dive into deep detail before getting on board. The question comes in the form of the old development methodology: "Let me see the high level plan and what the change will be in the deliverables and methodology over the next two years." This is exactly what you're trying to avoid by going to an Agile method.
  • try Agile on a few small projects, measure the results, talk to users about their satisfaction, and then readdress
  • nitiate the shift in the most change-prone areas first, and then work it backwards through the rest of the organization
  • It doesn't happen everywhere at all times, and it doesn't work in all areas. It's good to recognize that up front – that software development projects adapt to this easily, but an infrastructure project would have challenges with this approach. So, select a few areas that would naturally lend themselves to Agile, such as application development, gradually introduce it to these areas that need it most, and then measure results.
  • Again I'd say: "Try it." Agile transition is absolutely about organizational change. To win executive support we need to speak in terms of risk management, measurement and the bottom line.
Yuval Yeret

Kanban development oversimplified: a simple explanation of how Kanban adds to the ever-... - 0 views

agileproductdesign.com/...kanban_over_simplified.html

lean kanban

shared by Yuval Yeret on 03 Jun 09 - Cached
  • It’s a lot easier to estimate a story that’s small — which can lead to more accurate estimates, and better predictability.
  • It’s easier to plan with smaller stories. With big stories — stories that might take weeks for a developer to implement — it becomes difficult to plan a development time-box — particularly when the iterations are only a couple of weeks. It seems that only a couple stories fit — and there’s often room for half a story — but how do you build half a story? Splitting them into smaller stories makes it easier to plan those time-boxes.
  • Shrinking stories forces earlier elaboration and decision-making. Where product owners could write their stories fairly generally and consider many of the details later, now breaking them down into smaller stories forces more thinking earlier in a planning lifecycle.
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  • Managing little stories forces us to keep better track of how they fit together. Product owners are often asked to break down stories to a level where a single story becomes meaningless. To keep track of what’s meaningful to them and other stakeholders, they often need to keep track of bigger items such as the features of the product and how many stories contribute to building up that feature.
  • The result of these herniated time-box activities is a cycle that’s actually 3-4 times longer than our time-box. To get work done, we’ll use a time-box to elaborate stories, one to develop them, another to more thoroughly test them, and if there are bugs, possibly another to fix them.
  • During an ideal Agile time-box we’ll have frequent discussions between developers, testers, and those on a product owner team — like business analysts, user experience people, and business people. We’ll do this to understand what we need to build and describe what we’ll do to validate the story was really done. When time-boxes are short, there’s less time for this conversation. It’s common to move many of the conversations to detail the story and describe acceptance to the time-box before so we can be ready to really get moving with development when the time-box starts.
  • It’s difficult to fit thorough validation of the story into a short time-box as well. So, often testing slips into the time-box after. Which leaves the nasty problem of what to do with bugs� which often get piped into a subsequent time-box.
  • Anyone who’s attended an Agile planning meeting knows they can often last about an hour longer than you can stand it
  • As time-boxes shrink those on the product owner team and testers find themselves in a constant mode of getting ready for a next time-box and evaluating past time-boxes
  • work long hours, attend lots of meetings, and seem to have less time to be available to help developers with the current time-box. Since their focus is on a future or past time-box, questions about this time-box seem like interruptions. Collaboration decreases and tensions increase. Their work load is heavy, bumpy, not smooth or even.
  • Kanban cards are used to limit the amount of inventory the factory builds. It doesn’t do the Toyota factory any good to build doors faster then they can assemble cars. It just wastes money on excess doors, and parts of doors. Excess work in progress is considered to be waste in Lean manufacturing. (It’s probably waste in non-Lean manufacturing too.) In the above completely made up example, you’ll never have more than 15 finished doors hanging around. (Mudha is Japanese for waste. Learn it to impress your Lean friends.)
  • “Kan” means visual, and “ban” means card or board.
  • Kanban thinking in software development attempts to do a similar thing. We want to limit unnecessary work in progress to be no higher than it needs to be to match the throughput of the team.
  • In Kanban development: time-boxed development is out stories are larger and fewer estimation is optional or out completely velocity is replaced by cycle time
  • Exactly what’s left of Agile if we get rid of time-boxes, change the meaning of stories, and stop measuring velocity. And, exactly what do car doors and Kanban cards have to do with software development? Don’t get hung up on process. Remember, agile development isn’t a process.
  • You might have a column where business analysts spend time tracking down technical details that developers need to understand to write code.
  • These columns aren’t set. You should discuss with your team the phases that stories go through to be completed. Some organization may use columns for writing documentation, or preparing customer service people to support the feature in production.
  • The top is used for stories currently in progress in that phase. The bottom is the buffer. When work for that phase of the story is completed, it moves from “in progress” to the “buffer” where it’ll wait to be pulled into the next phase.
  • When we set limits for work in progress, we’ll set a total number for the process step that includes both “in process” and the “finished buffer” for that process step.
  • Stories must be minimal marketable features
  • To be marketable the feature needs to be large enough to be useful — probably larger than the teeny stories that take a couple days to build and seem to be best practice in Agile development today. A MMF may take weeks to build. But the important thing isn’t how long it takes to build, but that it be understandable and valuable to those who’ll receive it. To identify a MMF some folks ask the question “Would I announce it in my company’s product blog?” If it’s too tiny to mention, then it’s not a MMF.
  • To be lean, we’ll limit the number of stories we allow onto the board. A common formula is to add up all the members of the team in all roles and divide by two. All roles includes developers, analysts, user interfaced designers, testers, deployment people — anyone immediately responsible for getting features to market. For example, if team members total 20, we might limit the number of MMF-style stories on the board to 10.
  • Today developers have finished a story, and s they walk to the Kanban board to move it out of development, they notice their single buffer slot is full — and the “testing in progress” column is filled to its limit. What now? The developers talk to the testers. “We’re really struggling to keep up here. It’ll be till tomorrow morning before we can get some of these stories moved out.” “Hmm�” says a developer “Can we help test?” “Of course you can!” says the tester. “With your help we can get these cleared out by the end of the day.“ The tester grins “I just don’t want you validating a story you implemented.”
  • For the limits of the story process steps, the limit is often half the number of people that can perform the work for that phase of development. For instance if you have 6 developers, you might limit the development in progress column to 3. Now, this will force developers to work together on stories. I do find in practice that this may not work out for all teams — so I often see limits that equal the number of developers (or those that can perform the process step) or often 1.5 * the number of people in a role. Of course if you do this, it’ll raise the overall work in progress — and as you might expect, items will take longer to finish.
  • When a column in a Kanban board is full, we know that group is at capacity. We also know that if this keeps happening that that process step is likely where a bottleneck is.
  • If you’ve ever waited in line for the Pirates of the Caribbean in Disneyland you might remember signs along the way that say “Your wait time from here is 30 minutes” — something like that. Now you can post your own wait times on your Kanban board. At the bottom of your story queue post the average cycle time with wait time. It’ll say something like “Your wait time for a story here is approximately 18 days.” At the top of the queue post the average working cycle time. It might say “your wait time from here is 14 days.”
  • When you place focus on how quickly you can get functionality done, and have the ability to measure just that, then the estimates don’t much matter. In fact, many using a Kanban approach have simply stopped estimating at all. Yes story sizes vary, but being able to give a wait time plus or minus a few days is sufficient for many organizations’ concerns.
  • But, since there’s no development time-box in Kanban development, we’ll measure story-by-story how long they took to complete — the “cycle time” of the story.
  • Some do still estimate stories. Then use those estimates in conjunction with cycle time. Using a spreadsheet we can calculate the average cycle time for stories with a given estimate. If you do this, consider placing a handy chart next to your Kanban board showing estimate in one column, and wait times in adjacent columns. With this you’re answering the real question stakeholders are asking for when they get estimates: “when am I going to see this functionality in the software?”
  • If your stakeholders are like mine, they don’t want to know when they’re going to get this functionality, the want to know when they’re going to get all this functionality. I find that if I place stories into a spreadsheet with start and end dates, and calculate cycle time, if I select an arbitrary time period — say a two or three week time period — I can see how many stories where completed during this time period. For instance I might see the team finished 22 stories in 3 weeks — that’s about 7.3 stories per week. Given a backlog of 100 stories I can reasonably infer that it’ll take between 13 and 14 weeks (100/7.3). That’s yesterday’s weather for Kanban — at least the way I calculate it.
  • If I know that during three week time period there where 15 working days and that 5 developers worked the entire time, that’s 75 developer days. Knowing that lets me calculate the average number of developer days per story: 3.4 (75/22) — Which is darn close to pi — which makes me believe it has to be right. ;-) This number, 3.4, is what XP practitioners referred to as load factor.
  • Evaluation cycles, not development time-boxes
  • The only difference is the cycles aren’t used to plan and commit to stories any longer.
  • The daily standup or daily scrum meeting occurs as normal, but now it occurs in front of the Kanban board. Instead of the regular meeting ritual of checking in with each person to find out what they worked on yesterday and will work on today, the discussion revolves around the Kanban board and what will likely move on and off the board today, where “traffic” seems the heaviest, and what we could do to clear bottlenecks.
  • Reflect every few weeks
  • Lean practices help teams increase throughput. They don’t make developers type faster, rather they draw attention to bottlenecks that slow things down, help you see them and respond to them quicker. Using a Kanban board lets you easily visualize work in progress across different roles and lets you see when someone is taking on too much work simultaneously.
  • Demonstrate every few weeks
  • A task board as it’s commonly used in an agile approach can give you the visualization too. But, widening the task board to separate testing from development from acceptance or other process steps helps me better visualize where things are clogging up — helps me better diagnose problems. And, setting hard limits for process steps and respecting them really makes me deal with the problem in a way that dropping a pile of stories into a sprint or iteration didn’t. But, maybe it’s just me who’s lazy and avoids dealing with tough problems. I’m sure you’d never run into a situation where you and your team let lots of finished development work pile up waiting to be tested.
  • There’s no one as zealous as the newly converted There’s a lot of folks pretty excited about Kanban out there. I am too. Sometimes that zeal takes the form of telling people practicing common agile time-boxed development that they’re wrong. But, I guess I’m crusty enough to know that there’s lots of right ways to succeed and anyone who believes they’ve found the best ways is likely wrong. Don’t let those voicing opinions strongly for, or against, Kanban approaches stop you for digging in deeper and understanding the ideas behind it.
  • Yuval Yeret on 03 Jun 09
     
    one of the best articles about Kanban and its relation to Agile I've encountered so far - focusing on Feature development (not maintenance)
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